1. Field of the Invention
The present invention relates to a cap assembly capable of simplifying a manufacturing process and enhancing sealing performance and safety, and a secondary battery having the same.
2. Description of the Related Art
Secondary batteries can be recharged and repeatedly used even after having been discharged, so that they are widely used as an energy source for electronic devices in various applications.
Although secondary batteries were limited in use to mainly small electronic devices such as MP3s, cameras and PMPs due to small capacity in the past, as the secondary batteries achieve higher capacity and power, they are being designed to be used in hybrid cars and electric-powered tools.
Among these secondary batteries, a lithium secondary battery is widely used in various applications because of a high operating voltage and a high energy density per unit weight.
The lithium secondary battery is formed by accommodating an electrode assembly and an electrolyte in an outer case, and sealing the outer case.
Lithium secondary batteries may be classified into can- and pouch-type batteries according to the shape of the outer case. The can-type battery may be further classified into cylindrical and prismatic batteries.
The cylindrical secondary battery is formed by accommodating an electrode assembly and an electrolyte in a can, and inserting an insulating gasket and a cap assembly into an opening of the can to seal the can.
Generally, in the cylindrical secondary battery, the insulating gasket is inserted into the opening of the can, and components of the can assembly are inserted into the insulating gasket one by one, and a side surface of the can and the insulting gasket are then crimped to seal the can.
A secondary battery having the conventional cap assembly has a problem of decreased processibility since all components of the cap assembly are inserted individually.
Further, since the components of the cap assembly are simply stacked, the components are often weakly adhered to each other, and thus there is an increased risk of leakage of gases generated in the battery.